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Old 01-01-2019, 06:10 PM   #1
OldOfflineMan
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Join Date: Aug 2018
Location: Toronto
Posts: 384
Trypticon Tail and Hip Fix Experience

I recently bought a used Trypticon and it had both the common critical hip and tail joint issues that plague this otherwise wonderful toy. If left unfixed these issues will result in the joints completely breaking down and render the toy unplayable. There are a number of fixes available on Youtube and on tfw2005.com and I've documented here what I ultimately did to fix these critical issues.

The Trypticon I bought also had issues with the chest door being slightly too small (it doesn't fully lock) and a warped right panel (so the panel doesn't clip shut at the top near the neck), but these are very minor issues that can be fixed at a later date.


Hip Issue:

The issue here is the spring inside the hip ratchet joint is way too long, resulting in excessive force required to compress the spring enough for the ratchet to move (thus allowing the leg to move). The force comes from a thin cross piece in the hip (you'll see what I mean from my quoted video) which is not strong enough to sustain the force, eventually shattering and destroying the joint.

The best video I have found for the description of the problem and how to disassemble the joint is here:

https://www.youtube.com/watch?v=gf_5bS8HXi4

However, it prescribes pre-compressing the spring to fix this problem, but I am not entirely sure it is a long term fix. My reasoning is below:

Most springs follow Hooke's law. Let:
F = force required to compress the spring,
k = spring constant (how stiff the spring is),
x = amount the spring is compressed from its rest position.

Hooke's law states that:
F = kx

So essentially, the amount of force required to compress the spring further increases as the spring is compressed. It also implies there are two ways to reduce the force needed to compress the spring:

1) change the spring characteristics (either change the material or make the wire of the spring thinner), and/or,
2) change the length of the spring.

The solution in the quoted video does neither. It pre-compresses the spring to hold the ratchet in place, but then it still requires that excessive force to compress the spring further to allow the ratchet joint to move. So, I can:

1) Cut the spring (thus reduce "x"),
2) Soften the spring by keeping it over-compressed (thus reduce "k"), and/or
3) Replace the spring with another spring (thus reduce "k").

I didn't want to cut or soften the spring, as it is irreversible. I ended up using scrunched up newspaper/packing paper as a spring. The amount of paper stuffed into that joint controls how stiff that joint is. The joint does need to be a bit stiff or Trypticon won't hold a pose.

I don't recommend using lubricant on the teeth of the ratchet interface as some of the videos suggest, as lubricants have a bad habit of leaking out of an unsealed joint and/or degrading the plastic.


Tail Issue:

This thread describes the problem very well, and its prescribed solution is good in principle:

http://www.tfw2005.com/boards/thread...l-fix.1120326/

Two things I would change:

1) Don't use superglue. It is a horrible adhesive for plastic in toys as it easily fractures under the stress. I would follow Gotbot's suggestion in this thread (http://www.cybertron.ca/boards/showthread.php?t=74627) and use Bondic. That stuff is pretty close to plastic welding.

2) When you get to the step where he says "You may well be able to pry out that piece of the assembly but I couldn't so now we resort to spatchcocking our Trypticon and take the body apart to get to that bloody thing", it is not necessary to disassemble the entire Trypticon, just simply poke out the remaining piece of the ratchet joint from the other side.


After doing these critical fixes, Trypticon moves as he's meant to (and I can play with him with ease of mind).

Happy fixing!
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Last edited by OldOfflineMan; 01-02-2019 at 01:39 PM.
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